Contents
- Weather in December
- Frequently asked questions
- Average temperature in December
- Average pressure in December
- Average wind speed in December
- Average humidity in December
- Average rainfall in December
- Average rainfall days in December
- Average daylight in December
- Average sunshine in December
- Average sunshine days in December
- Average UV index in December
- Average cloud cover in December
- Average visibility in December
Weather in December
Temperature
The lowest temperatures are recorded in December, with averages reaching a high of 55.6°F (13.1°C) and a low of 47.8°F (8.8°C).Humidity
The average relative humidity in December in Millbrae, California, is 72%.Rainfall
In December, in Millbrae, the rain falls for 11.1 days. Throughout December, 2.17" (55mm) of precipitation is accumulated. Throughout the year, there are 81.5 rainfall days, and 12.8" (325mm) of precipitation is accumulated.Daylight
The month with the shortest days is December, with an average of 9h and 36min of daylight.On the first day of the month, sunrise is at 7:06 am and sunset at 4:51 pm. On the last day of December, in Millbrae, California, sunrise is at 7:24 am and sunset at 5:01 pm PST.
Sunshine
December has the least sunshine of the year in Millbrae, with an average of 5.8h of sunshine.UV index
The months with the lowest UV index in Millbrae are February and December, with an average maximum UV index of 3. A UV Index reading of 3 to 5 represents a medium health hazard from exposure to the Sun's UV rays for the ordinary person.Note: A maximum daily UV index of 3 during December morphs into the following directions:
Be cautious. Those with fair skin can be subjected to burns in fewer than 30 minutes. Minimize direct exposure to the Sun during midday when its radiation is at its peak. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes.
Frequently asked questions
What month is the coldest in Millbrae?
What is the temperature in December in Millbrae?
What is the average humidity in December in Millbrae?
How many days does it rain in December in Millbrae?
What is the month with the shortest days in Millbrae?
How many hours of daylight does Millbrae have in December?
When are sunrise and sunset in December in Millbrae?
What is the month with the least sunshine in Millbrae?
How long on average sun shines in December in Millbrae?
What is the month with the lowest UV index in Millbrae?
What is the UV index intensity in December in Millbrae?
Average temperature in December
Millbrae, CA
- Average high temperature in December: 55.6°F
The warmest month (with the highest average high temperature) is September (70.2°F).
The month with the lowest average high temperature is December (55.6°F).
- Average low temperature in December: 47.8°F
The month with the highest average low temperature is September (56.8°F).
The coldest month (with the lowest average low temperature) is January (47.5°F).
Average pressure in December
Millbrae, CA
- Average pressure in December: 30.11"Hg
The month with the highest atmospheric pressure is January (30.13"Hg).
The month with the lowest atmospheric pressure is September (29.92"Hg).
Average wind speed in December
Millbrae, CA
- Average wind speed in December: 7.2mph
The windiest month (with the highest average wind speed) is April (8.3mph).
The calmest month (with the lowest average wind speed) is September (6.1mph).
Average humidity in December
Millbrae, CA
- Average humidity in December: 72%
The month with the highest relative humidity is August (78%).
The month with the lowest relative humidity is October (70%).
Average rainfall in December
Millbrae, CA
- Average rainfall in December: 2.17"
The wettest month (with the highest rainfall) is February (2.44").
The driest month (with the least rainfall) is July (0.08").
Average rainfall days in December
Millbrae, CA
- Average rainfall days in December: 11.1 days
The month with the highest number of rainy days is March (12.8 days).
The months with the least rainy days are June and July (2.4 days).
Average daylight in December /
Average sunshine in December
Millbrae, CA
- Average daylight in December: 9h and 4min
The month with the longest days is June (Average daylight: 14h and 42min).
The month with the shortest days is December (Average daylight: 9h and 36min).
- Average sunshine in December: 5h and 5min
The month with the most sunshine is July (Average sunshine: 11h and 48min).
The month with the least sunshine is December (Average sunshine: 5h and 48min).
Average sunshine days in December
Millbrae, CA
- Average sunshine days in December: 19.1 days
The month with the most sunshine days is July (24.6 days).
The month with the least sunshine days is March (16.3 days).
Average UV index in December
Millbrae, CA
- Average UV index in December: 3
The months with the highest UV index are June, July, August and September (UV index 5).
The months with the lowest UV index are February and December (UV index 3).
Average cloud cover in December
Millbrae, CA
- Average cloud cover in December: 35
The month with the most cloud cover is March (Cloud cover 36).
The months with the least cloud cover are July and September (Cloud cover 15).
Average visibility in December
Millbrae, CA
- Average visibility in December: 6mi
The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
Millbrae, California, USA
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